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Seagull Poo

Scientists are only human, and one of the defining features of humanity is the ability to snigger at the thought of bodily waste. Which was why the Carnal Carnival was set up, in a twittered flurry of excitement to cover all such bodily functions normally thought of as disgusting. And of course my main thought, when I saw all those eukaryote-specific processes going up on the topic list, was "How many of those can I twist into a post about bacteria"

The first topic was poo - which automatically suggests human gut bacteria to anyone who knows anything about bacteria, but unfortunately everyoneand their mum has already covered that. So I surfed around Google Scholar for a bit and finally found something quite interesting and less (to my mind) disgusting: there are people out there who spend their time researching seagull poo.

>This picture tells you all you need to know about seagulls

The first thing that came into my mind at that point was "why seagulls?" Studying the gut bacteria of farmyard animals I can understand, because they interact with humans a lot. Animals meant for food would also make sense, in order to trace sources of possible bacterial contamination. But when you think about it seagulls, particularly in the UK (I'm not sure about other countries, as I've no first hand experience) are pretty much endemic. Every time you walk along a beach, swim outdoors, go coastal walking or rockclimbing, chances are you are interacting with seagull poo.

Most studies looking at gut microbes in animals tend to do it by growing cultures and looking for specific bacteria, usually the disease causing ones. As this is a limited approach the more fashionable thing to do nowadays is to do a PCR analysis of all the bacterial DNA in the poo, find the bits that look like bacterial ribosome RNA and use that to identify which bacteria are present. This is a more wide-sweeping approached that identifies a lot more bacterial species and allows more accurate comparisons of which species is found in which sample.

The most commonly found bacteria in seagull poo were bacilli - a genus containing the classes of bacillus and lactobacillus (of yogurt fame). One of the most common bacteria was a little gram positive called C. marimammalium which has been found in other animals with a marine diet, such as seals and some waterfowl. This is different to the composition of bacteria found in the guts of domestic birds such as chickens, which tend to contain more pathogenic strains (such as Campylobacter jejuni and Salmonella - both of which can cause serious illness).

The C. marimammalium was found to be so prevalent that it could easily be used as a marker for gull poo, particularly useful in determining sources of contamination. Having gull-specific markers for contamination by poo can help beach managers better assess potential causes of contamination (seagulls or waste dumping?) allowing them to implement clean-up strategies that target the correct source of the pollution. Unfortunately, it also means that your parents will never boast to their friends about all the important work on seagull poo that you're doing for science.

7 comments:

One of the few things more obnoxious than seagulls has got to be seagull poo, but I'm glad you've convinced me of the usefulness of 'markers for gull poo' ;).On a more serious note: is their anything known about why C. marimammalium is such a fan of mammals with marine diets? For example, can it degrade unsaturated fatty acids (abundant in fish) particularly well?

I wish somebody would do the same thing for vultures. The common turkey vulture's excrement is supposed to have antimicrobial qualities -- something about keeping their feet from getting infected -- but how can that be?

the more fashionable thing to do nowadays is to do a PCR analysis of all the bacterial DNA in the poo

The even more fashinable thing is to extract all the DNA you can from the feces, sequence everything using 2nd gen tech, and align it against the entire NCBI database. OR, to be even more fancy, extract the RNA, turn it into cDNA, sequence it all, align it against all known gene families, and use that to make judgements about the transcribed functionality of the gut micobiome.